/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    Remove.java
 *    Copyright (C) 1999 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Range;
import weka.core.RevisionUtils;
import weka.core.SparseInstance;
import weka.core.Utils;
import weka.core.Capabilities.Capability;
import weka.filters.Filter;
import weka.filters.StreamableFilter;
import weka.filters.UnsupervisedFilter;

import java.util.Enumeration;
import java.util.Vector;

/**
 * <!-- globalinfo-start --> A filter that removes a range of attributes from
 * the dataset. Will re-order the remaining attributes if invert matching sense
 * is turned on and the attribute column indices are not specified in ascending
 * order.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -R &lt;index1,index2-index4,...&gt;
 *  Specify list of columns to delete. First and last are valid
 *  indexes. (default none)
 * </pre>
 * 
 * <pre>
 * -V
 *  Invert matching sense (i.e. only keep specified columns)
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Len Trigg (trigg@cs.waikato.ac.nz)
 * @version $Revision: 7107 $
 */
public class Remove extends Filter implements UnsupervisedFilter,
		StreamableFilter, OptionHandler {

	/** for serialization */
	static final long serialVersionUID = 5011337331921522847L;

	/** Stores which columns to select as a funky range */
	protected Range m_SelectCols = new Range();

	/**
	 * Stores the indexes of the selected attributes in order, once the dataset
	 * is seen
	 */
	protected int[] m_SelectedAttributes;

	/**
	 * Constructor so that we can initialize the Range variable properly.
	 */
	public Remove() {

		m_SelectCols.setInvert(true);
	}

	/**
	 * Returns an enumeration describing the available options.
	 * 
	 * @return an enumeration of all the available options.
	 */
	public Enumeration listOptions() {

		Vector newVector = new Vector(2);

		newVector.addElement(new Option(
				"\tSpecify list of columns to delete. First and last are valid\n"
						+ "\tindexes. (default none)", "R", 1,
				"-R <index1,index2-index4,...>"));
		newVector.addElement(new Option(
				"\tInvert matching sense (i.e. only keep specified columns)",
				"V", 0, "-V"));

		return newVector.elements();
	}

	/**
	 * Parses a given list of options.
	 * <p/>
	 * 
	 * <!-- options-start --> Valid options are:
	 * <p/>
	 * 
	 * <pre>
	 * -R &lt;index1,index2-index4,...&gt;
	 *  Specify list of columns to delete. First and last are valid
	 *  indexes. (default none)
	 * </pre>
	 * 
	 * <pre>
	 * -V
	 *  Invert matching sense (i.e. only keep specified columns)
	 * </pre>
	 * 
	 * <!-- options-end -->
	 * 
	 * @param options
	 *            the list of options as an array of strings
	 * @throws Exception
	 *             if an option is not supported
	 */
	public void setOptions(String[] options) throws Exception {

		String deleteList = Utils.getOption('R', options);
		if (deleteList.length() != 0) {
			setAttributeIndices(deleteList);
		}
		setInvertSelection(Utils.getFlag('V', options));

		if (getInputFormat() != null) {
			setInputFormat(getInputFormat());
		}
	}

	/**
	 * Gets the current settings of the filter.
	 * 
	 * @return an array of strings suitable for passing to setOptions
	 */
	public String[] getOptions() {

		String[] options = new String[3];
		int current = 0;

		if (getInvertSelection()) {
			options[current++] = "-V";
		}
		if (!getAttributeIndices().equals("")) {
			options[current++] = "-R";
			options[current++] = getAttributeIndices();
		}

		while (current < options.length) {
			options[current++] = "";
		}
		return options;
	}

	/**
	 * Returns the Capabilities of this filter.
	 * 
	 * @return the capabilities of this object
	 * @see Capabilities
	 */
	public Capabilities getCapabilities() {
		Capabilities result = super.getCapabilities();
		result.disableAll();

		// attributes
		result.enableAllAttributes();
		result.enable(Capability.MISSING_VALUES);

		// class
		result.enableAllClasses();
		result.enable(Capability.MISSING_CLASS_VALUES);
		result.enable(Capability.NO_CLASS);

		return result;
	}

	/**
	 * Sets the format of the input instances.
	 * 
	 * @param instanceInfo
	 *            an Instances object containing the input instance structure
	 *            (any instances contained in the object are ignored - only the
	 *            structure is required).
	 * @return true if the outputFormat may be collected immediately
	 * @throws Exception
	 *             if the format couldn't be set successfully
	 */
	public boolean setInputFormat(Instances instanceInfo) throws Exception {

		super.setInputFormat(instanceInfo);

		m_SelectCols.setUpper(instanceInfo.numAttributes() - 1);

		// Create the output buffer
		FastVector attributes = new FastVector();
		int outputClass = -1;
		m_SelectedAttributes = m_SelectCols.getSelection();
		for (int i = 0; i < m_SelectedAttributes.length; i++) {
			int current = m_SelectedAttributes[i];
			if (instanceInfo.classIndex() == current) {
				outputClass = attributes.size();
			}
			Attribute keep = (Attribute) instanceInfo.attribute(current).copy();
			attributes.addElement(keep);
		}
		// initInputLocators(instanceInfo, m_SelectedAttributes);
		initInputLocators(getInputFormat(), m_SelectedAttributes);
		Instances outputFormat = new Instances(instanceInfo.relationName(),
				attributes, 0);
		outputFormat.setClassIndex(outputClass);
		setOutputFormat(outputFormat);
		return true;
	}

	/**
	 * Input an instance for filtering. Ordinarily the instance is processed and
	 * made available for output immediately. Some filters require all instances
	 * be read before producing output.
	 * 
	 * @param instance
	 *            the input instance
	 * @return true if the filtered instance may now be collected with output().
	 * @throws IllegalStateException
	 *             if no input structure has been defined.
	 */
	public boolean input(Instance instance) {

		if (getInputFormat() == null) {
			throw new IllegalStateException("No input instance format defined");
		}
		if (m_NewBatch) {
			resetQueue();
			m_NewBatch = false;
		}

		if (getOutputFormat().numAttributes() == 0) {
			return false;
		}
		double[] vals = new double[getOutputFormat().numAttributes()];
		for (int i = 0; i < m_SelectedAttributes.length; i++) {
			int current = m_SelectedAttributes[i];
			vals[i] = instance.value(current);
		}
		Instance inst = null;
		if (instance instanceof SparseInstance) {
			inst = new SparseInstance(instance.weight(), vals);
		} else {
			inst = new Instance(instance.weight(), vals);
		}
		inst.setDataset(getOutputFormat());
		copyValues(inst, false, instance.dataset(), getOutputFormat());
		inst.setDataset(getOutputFormat());
		push(inst);
		return true;
	}

	/**
	 * Returns a string describing this filter
	 * 
	 * @return a description of the filter suitable for displaying in the
	 *         explorer/experimenter gui
	 */
	public String globalInfo() {

		return "A filter that removes a range of"
				+ " attributes from the dataset. Will "
				+ "re-order the remaining attributes "
				+ "if invert matching sense is turned "
				+ "on and the attribute column indices "
				+ "are not specified in ascending order.";
	}

	/**
	 * Returns the tip text for this property
	 * 
	 * @return tip text for this property suitable for displaying in the
	 *         explorer/experimenter gui
	 */
	public String invertSelectionTipText() {

		return "Determines whether action is to select or delete."
				+ " If set to true, only the specified attributes will be kept;"
				+ " If set to false, specified attributes will be deleted.";
	}

	/**
	 * Get whether the supplied columns are to be removed or kept
	 * 
	 * @return true if the supplied columns will be kept
	 */
	public boolean getInvertSelection() {

		return !m_SelectCols.getInvert();
	}

	/**
	 * Set whether selected columns should be removed or kept. If true the
	 * selected columns are kept and unselected columns are deleted. If false
	 * selected columns are deleted and unselected columns are kept.
	 * 
	 * @param invert
	 *            the new invert setting
	 */
	public void setInvertSelection(boolean invert) {

		m_SelectCols.setInvert(!invert);
	}

	/**
	 * Returns the tip text for this property
	 * 
	 * @return tip text for this property suitable for displaying in the
	 *         explorer/experimenter gui
	 */
	public String attributeIndicesTipText() {

		return "Specify range of attributes to act on."
				+ " This is a comma separated list of attribute indices, with"
				+ " \"first\" and \"last\" valid values. Specify an inclusive"
				+ " range with \"-\". E.g: \"first-3,5,6-10,last\".";
	}

	/**
	 * Get the current range selection.
	 * 
	 * @return a string containing a comma separated list of ranges
	 */
	public String getAttributeIndices() {

		return m_SelectCols.getRanges();
	}

	/**
	 * Set which attributes are to be deleted (or kept if invert is true)
	 * 
	 * @param rangeList
	 *            a string representing the list of attributes. Since the string
	 *            will typically come from a user, attributes are indexed from
	 *            1. <br>
	 *            eg: first-3,5,6-last
	 */
	public void setAttributeIndices(String rangeList) {

		m_SelectCols.setRanges(rangeList);
	}

	/**
	 * Set which attributes are to be deleted (or kept if invert is true)
	 * 
	 * @param attributes
	 *            an array containing indexes of attributes to select. Since the
	 *            array will typically come from a program, attributes are
	 *            indexed from 0.
	 */
	public void setAttributeIndicesArray(int[] attributes) {

		setAttributeIndices(Range.indicesToRangeList(attributes));
	}

	/**
	 * Returns the revision string.
	 * 
	 * @return the revision
	 */
	public String getRevision() {
		return RevisionUtils.extract("$Revision: 7107 $");
	}

	/**
	 * Main method for testing this class.
	 * 
	 * @param argv
	 *            should contain arguments to the filter: use -h for help
	 */
	public static void main(String[] argv) {
		runFilter(new Remove(), argv);
	}
}
